So who was she living with when she attended the Punahou school from 1984 to 1988, since mom was Indonesia and Pakistan at that time?
Here are a couple of excerpts which also confirm your statement:
(1) Obama’s grandparents maneuvered him into Punahou; his grandfather’s boss, an alumnus, intervened to have Obama accepted. And Madelyn’s job at the bank helped pay the steep tuition. By living in a modest apartment and sending Obama (and eventually Maya) to private school, his grandparents had sacrificed their own prosperity for the sake of Obama and his sister. “We never suffered,” Madelyn answered when I asked what specific things were given up to send her grandchildren to Punahou. “As you can see, we live in an apartment instead of a house….But I think we could have done the other if we had wanted. But I traveled, you know, and spent money on the kids – the kids and traveling were priorities. (From Promise to Power David Mendell pg 36)
(2) She [Madelyn] took care of the family financially, making it possible for Barack and me [Maya] to maneuver through life, knowing that we could take some risks because she provided us a safety net.” (Obamaland by Ron Jacobs pg 95)